1. Field of Invention
The present invention relates to touch sensing techniques. More particularly, the present invention relates to touch sensing techniques and their application to a portable electronic apparatus.
2. Description of Related Art
A modern touch panel has advantages, such as being user-friendly, fast response times, compact size, etc. The touch panel may provide users a convenient and intuitive way to manipulate an electronic device. Therefore, touch panels are widely used in all kinds of consumer electronics, e.g., e-books, personal digital assistants (PDAs), smart phones, laptop computers, point of sale (POS) systems, etc.
In general, a touch panel is formed by a display panel and a touch sensor module disposed on the display panel. A transparent touch sensor film is adhered on the display panel, so as to realize touch sensing and display functions at the same time. Because of recent improvements made in the sensing precision of the aforesaid touch-sensing equipment, the modern touch panel is now popular among users, and it is gradually replacing traditional input devices, e.g., keyboards and mouse devices, in many systems.
Currently, a Graphical User Interface (GUI) is typically used as the user interface in a touch panel. There are several objects, e.g., functional shortcuts or Widgets, displayed on the desktop of the Graphical User Interface.
The objects displayed on the desktop are distributed on different spots in two dimensions over the screen. When a user touches the touch sensor module, a touch input with a horizontal coordinate and a vertical coordinate is induced. On the basis of the horizontal coordinate and the vertical coordinate of the touch input, a corresponding object on the user interface can be selected or an application function of the object can be executed.
Several kinds of touch sensing technologies have been developed, including those based on resistive, surface acoustic wave, surface capacitive, projected capacitive, infrared, and optical imaging techniques.
Recently, some devices with multi-touch input functions based on capacitive sensing techniques have been well-received. Therefore, both the sensing capability and production technology of capacitive sensors have improved considerably in recent times. In general, the capacitive sensor detects the capacitance variance between arranged transparent electrodes in response to human finger contact, and determines the contact coordinates according to the induced current caused by the finger contact.
However, the capacitive touch panel may only react to an electrostatic object with conductivity, e.g., a finger, and can not detect a non-electrostatic object without conductivity, e.g., a stylus. As a result, the scope of application of capacitive touch panel is limited.